react-mcp

name	react-mcp
description	Lets end users add, authenticate, and manage MCP servers from the browser in assistant-ui apps with @assistant-ui/react-mcp. Use when building user-managed MCP server UIs: mounting McpManagerResource via useAui({ mcp }), declaring presets with defineConnector, dropping in McpConfigDialog, or composing McpManagerPrimitive (Root, Connectors, CustomServers, AddCustomTrigger), McpServerPrimitive (Root, Name, Icon, Status, ConnectButton, DisconnectButton, OAuthLink, RemoveButton, Error), and McpAddFormPrimitive (NameField, UrlField, AuthSelect, AuthFields, Submit, Cancel). Covers auth modes none/bearer/oauth, the OAuth flow with McpOAuthCallback, connection states, storage via McpLocalStorage/McpMemoryStorage/McpCustomStorage, reading state with useAuiState (s.mcp, s.mcpServer), and imperative addCustomServer/connect/callTool. Distinct from developer-defined backend @ai-sdk/mcp tools in the tools skill. Reach for this when connected-server tools are missing, OAuth never completes, or servers do not persist.
license	MIT

assistant-ui React MCP

Always consult assistant-ui.com/llms.txt for the latest API.

Let end users add, authenticate, and manage MCP servers from the browser with @assistant-ui/react-mcp. The connected servers' tools are merged into the chat runtime automatically.

Contents

• References | Routes vs tools | Mount the manager | Drop-in dialog | Compose from primitives | OAuth connect flow | Custom storage | Imperative API | Common Gotchas | Related Skills

References

• ./references/setup.md -- McpManagerResource, defineConnector, storage, useAui({ mcp })
• ./references/ui.md -- McpManagerPrimitive / McpServerPrimitive / McpConfigDialog
• ./references/oauth.md -- OAuth connect flow and auth modes

Routes vs tools

This skill is for user-managed MCP servers: the end user picks and authenticates servers at runtime in the browser. Each server's tools are namespaced as serverId__toolName and exposed to the chat runtime with no extra wiring.

For developer-defined tools (frontend makeAssistantTool, backend AI SDK tool(), custom tool-call UI), use the tools skill instead. The two compose: a chat built with useChatRuntime can use both app tools and user-connected MCP tools at once.

Mount the manager

McpManagerResource({ connectors }) builds the mcp scope; pass it to useAui and wrap the app in AuiProvider. Connectors are presets declared with defineConnector.

"use client";
import { AuiProvider, useAui } from "@assistant-ui/react";
import { McpManagerResource, defineConnector } from "@assistant-ui/react-mcp";

const connectors = [
  defineConnector({
    id: "linear",
    name: "Linear",
    url: "https://mcp.linear.app",
    auth: { type: "oauth", scopes: ["read"] },
    icon: "/icons/linear.svg",
  }),
  defineConnector({
    id: "weather",
    name: "Weather",
    url: "https://mcp.example.com/weather",
    auth: { type: "none" },
  }),
];

export function Providers({ children }: { children: React.ReactNode }) {
  const aui = useAui({ mcp: McpManagerResource({ connectors }) });
  return <AuiProvider value={aui}>{children}</AuiProvider>;
}

Defaults: storage is McpLocalStorage(), oauthRedirectUri is ${window.location.origin}/mcp/callback, and autoConnect is true.

Drop-in dialog

McpConfigDialog is the shadcn dialog that lists connectors and custom servers with inline auth controls and an add form. Drop it anywhere under the provider.

import { McpConfigDialog } from "@/components/assistant-ui/mcp-config";

export default function Page() {
  return (
    <header className="flex items-center justify-between">
      <h1>My app</h1>
      <McpConfigDialog />
    </header>
  );
}

Pass children to override the default trigger: <McpConfigDialog><Button>Servers</Button></McpConfigDialog>.

Compose from primitives

McpManagerPrimitive iterates servers; nested McpServerPrimitive.* reads each item's scope automatically. Conditional buttons render only when the connection state matches.

"use client";
import { McpManagerPrimitive, McpServerPrimitive } from "@assistant-ui/react-mcp";

const ServerCard = () => (
  <McpServerPrimitive.Root>
    <McpServerPrimitive.Icon />
    <McpServerPrimitive.Name />
    <McpServerPrimitive.Status />
    <McpServerPrimitive.ConnectButton>Connect</McpServerPrimitive.ConnectButton>
    <McpServerPrimitive.DisconnectButton>Disconnect</McpServerPrimitive.DisconnectButton>
    <McpServerPrimitive.OAuthLink>Authorize</McpServerPrimitive.OAuthLink>
    <McpServerPrimitive.RemoveButton>Remove</McpServerPrimitive.RemoveButton>
    <McpServerPrimitive.Error />
  </McpServerPrimitive.Root>
);

export default function McpPage() {
  return (
    <McpManagerPrimitive.Root>
      <h2>Connectors</h2>
      <McpManagerPrimitive.Connectors>{() => <ServerCard />}</McpManagerPrimitive.Connectors>
      <h2>Your servers</h2>
      <McpManagerPrimitive.CustomServers>{() => <ServerCard />}</McpManagerPrimitive.CustomServers>
      <McpManagerPrimitive.AddCustomTrigger>Add custom server</McpManagerPrimitive.AddCustomTrigger>
    </McpManagerPrimitive.Root>
  );
}

RemoveButton is hidden on connectors (presets cannot be removed). Omit AddCustomTrigger and CustomServers to disable user-added servers. Build the add form with McpAddFormPrimitive (Root, NameField, UrlField, AuthSelect, AuthFields, Error, Submit, Cancel); see ui.md.

OAuth connect flow

auth is one of { type: "none" }, { type: "bearer", token? }, or { type: "oauth", scopes?, ... }. For OAuth, add a callback route at the configured oauthRedirectUri and render McpOAuthCallback inside the same provider so it can finish the handshake.

"use client";
import { McpOAuthCallback } from "@assistant-ui/react-mcp";
import { useRouter } from "next/navigation";
import { Providers } from "../../providers";

export default function Callback() {
  const router = useRouter();
  return (
    <Providers>
      <McpOAuthCallback onComplete={() => router.replace("/mcp")} />
    </Providers>
  );
}

See oauth.md for the full auth-mode shapes and connection-state values (connected, connecting, authRequired, authPending, error, disconnected).

Custom storage

Replace the default McpLocalStorage() to persist custom servers and auth state on a backend (use McpMemoryStorage() for SSR/tests).

import { McpManagerResource, McpCustomStorage } from "@assistant-ui/react-mcp";

const aui = useAui({
  mcp: McpManagerResource({
    connectors,
    storage: McpCustomStorage({
      loadCustomServers: async () => fetch("/api/mcp/servers").then((r) => r.json()),
      saveCustomServers: async (records) =>
        fetch("/api/mcp/servers", { method: "PUT", body: JSON.stringify(records) }),
      loadAuthState: async (id) =>
        fetch(`/api/mcp/auth/${id}`).then((r) => (r.ok ? r.json() : null)),
      saveAuthState: async (id, state) =>
        fetch(`/api/mcp/auth/${id}`, { method: "PUT", body: JSON.stringify(state) }),
      clearAuthState: async (id) => fetch(`/api/mcp/auth/${id}`, { method: "DELETE" }),
    }),
  }),
});

Imperative API

Inside event handlers, drive the manager through useAui().mcp().

const aui = useAui();
await aui.mcp().addCustomServer({ name, url, auth: { type: "bearer", token } });
await aui.mcp().server({ id }).connect();
await aui.mcp().server({ id }).callTool("echo", { text: "hi" });

Read reactive state with useAuiState, scoped under s.mcp (manager) and s.mcpServer (current item inside a McpServerPrimitive subtree):

const isHydrated = useAuiState((s) => s.mcp.isHydrated);
const connectionState = useAuiState((s) => s.mcpServer.connectionState);

Common Gotchas

Tools not appearing in chat

• The server must reach the connected state; check McpServerPrimitive.Status or s.mcpServer.connectionState.
• Tool names are prefixed serverId__toolName; reference that exact name in tool UI.

OAuth never completes

• The callback route path must match oauthRedirectUri (default /mcp/callback).
• McpOAuthCallback must be rendered inside the same provider as the manager.

Servers not persisting / SSR errors

• Default McpLocalStorage() needs the browser; use McpMemoryStorage() or McpCustomStorage(...) on the server.

Custom server cannot be removed

• RemoveButton hides on connector presets by design; only user-added servers are removable.

Transport

• Only StreamableHTTP is supported; resources, prompts, sampling, and auto-reconnect are not yet wired.

Related Skills

• tools -- developer-defined frontend/backend tools and custom tool-call UI (makeAssistantTool, AI SDK tool(), makeAssistantToolUI); the complement to user-managed MCP servers.
• setup -- scaffold with the mcp template (npx assistant-ui@latest create -t mcp) and pick a runtime.
• runtime -- the chat runtime (useChatRuntime) that MCP tools are merged into.